define_method_experimentation.rb

[19] pry(main)> class Foo
[19] pry(main)*   define_method :foo do
[19] pry(main)*     puts 'foo'
[19] pry(main)*   end  
[19] pry(main)* end  
=> #<Proc:0xb5897e4c@(pry):33>
[20] pry(main)> Foo.new.foo
foo
=> nil
[21] pry(main)> class Foo
[21] pry(main)*   define_method :foo { puts 'foo' }
SyntaxError: unexpected '}', expecting kEND

Solution:

define_method(:foo) { puts 'foo' }